1. Field of the Invention
The invention relates to a vehicle roof having a roof opening system.
2. Related Technology
Such a vehicle roof is known from practice and comprises, in particular, a roof opening system which is embodied as what is referred to as an externally running sun roof. In such a sun roof, a roof opening is optionally closed or opened by means of a cover element which, in order to reach its open position is moved by means of a rear-side fixed roof area. The cover element is provided with a front and rear sliding element on each side of a longitudinal plane of the vehicle. The front sliding elements are each connected to a drive cable which is rigid in compression and is driven by a drive motor. During the opening movement, the rear sliding elements run along passively. The front sliding elements are guided in guide rails which lie in a dry area which is separated from a wet area by a separating device which surrounds the roof opening. The rear sliding elements are guided in guide rails which lie in this wet area. Furthermore, in order to carry out a deployment movement of the cover element during its opening movement, the activation mechanism of the roof opening system comprises what are referred to as auxiliary levers which are guided in corresponding guide rails within the dry area and dip through when the cover element moves back under the separating device which separates the dry area from the wet area. In the rear area of the cover element, two mechanical assemblies are therefore necessary, specifically one mechanical assembly which lies inside the separating device in the dry area and which constitutes the auxiliary lever, and one mechanical assembly to which the movement of the cover element outside the separating element is transmitted and which is arranged in the wet area.
In the roof opening system which is described above, the driven part of the mechanism therefore lies in the dry area. This is due to the fact that a drive motor and the associated electronics are not configured for the wet area, and a seal of the electronics would be expensive and complex. Furthermore, the drive cables are wound with helical rising cables so that a pinion which is driven by the drive motor can engage on said rising cables, and the torque of the drive motor can be converted into a thrust force. The drive cables which are rigid in compression cannot be effectively sealed against water.
In the roof opening system described there is also the disadvantage that the guide rails for the front sliding elements and the guide rails for the rear sliding elements are offset with respect to one another in the transverse direction of the vehicle. This occurs at the expense of the maximum dimensions of the roof opening in the transverse direction of the vehicle. Owing to the necessary protrusions of the cover in front of and behind the separating device between the wet area and the dry area, and owing to the necessary cover openings, the entire roof opening in the respective vehicle between the front-side roof frame area and the rear-side roof frame area is too short to arrange the guide rails of the front sliding elements and the guide rails of the rear sliding elements in a line.
The deployment movement of the cover element into a ventilator position generally occurs in previously known roof opening systems of the type described in the introduction by means of a lever/levers, or carriages with a lever or the like which lie in the region of the cover element rear edge in the dry area since the cover element can only be driven within the main seal or the separating element. As a result, the part of the drive mechanism on the front side of the vehicle has to remain stationary in front of a rear deployment element on the rear side of the vehicle, or the part of the drive mechanism on the front side of the vehicle has to move next to the deployment element on the rear side of the vehicle, which occurs at the expense of the dimensions of the roof opening in the transverse direction of the vehicle, or, as in the prior art described in the introduction, the rear-side deployment element has to move through under the separating element or the main seal, which again occurs at the expense of the head room in the passenger compartment of the vehicle.
Furthermore, the fact that the guide rails which are arranged one behind the other are offset with respect to one another in the transverse direction of the vehicle means that installation space is required which on some occasions is very difficult to provide in vehicle roofs. The overlapping of the rear and of the front guide rails in the longitudinal direction of the vehicle meant that previously it was only possible to provide a reinforcement element which satisfied the minimum requirements and which connected the two roof edges to one another, since such a reinforcement element would otherwise penetrate the main plane of the mechanism. For this reason, in the known designs, the reinforcement element is led past under the guide rails. However, this reinforcement element was previously a very flat design owing to the lack of installation space in the head area, and this in turn occurs at the expense of the flexural rigidity of the reinforcement element.